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Monomer Reactivity Ratios (monomer + reactivity_ratio)
Selected AbstractsSynthesis and Characterization of Poly(N -vinylimidazole- co -acrylonitrile) and Determination of Monomer Reactivity RatiosMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2004Nursel Pekel Abstract Summary: Radical-initiated solution copolymerization of N -vinylimidazole (VIM) and acrylonitrile (AN) was carried out with 2,2, -azobisisobutyronitrile (AIBN) as an initiator in benzene at 70,°C in nitrogen atmosphere. The structure and composition of synthesized copolymers for a wide range of monomer feeds were determined by FTIR, 1H and 13C NMR spectroscopy with the aid of recorded analytical absorption bands for VIM (667 cm,1, CN of imidazole ring) and AN (2,242 cm,1, CN group), as well as by using the areas of proton and carbon atom signals from corresponding functional groups of monomer units. Monomer reactivity ratios for VIM (M1)-AN (M2) pair were determined by nonlinear regression (NLR), Kelen,Tüdös (KT) and Fineman,Ross (FR) methods. They were found to be r1,=,0.24 and r2,=,0.15 for the NLR method, r1,=,0.22 and r2,=,0.094 for the KT method, and r1,=,0.24 and r2,=,0.12 for the FR method, respectively. The relatively high activity observed of VIM growing macroradical and the results of FTIR and 1H NMR structural analysis of copolymers suggest the formation of complexed linkages between monomers and growing radicals in chain propagation reactions. Similar complexation between monomer,comonomer units in the structure of formed macromolecules showed an increase in isotactic triad fractions in the copolymer. Complex formation between the imidazole ring and nitrile group in both the monomer mixture and chain growing reactions. [source] Monomer reactivity ratios of the 2-(3-mesityl-3-methylcyclobutyl)-2-hydroxyethyl methacrylate and styrene system from 1H NMRJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2002Ibrahim Erol Abstract 2-(3- Mesityl-3-methylcyclobutyl)-2-hydroxyethyl methacrylate (MCHEMA) was prepared from the reaction of methacrylic acid with the oxirane compound obtained from the chlorhydrin formed in the cyclization of 1-chloro-2,3-epoxy-5-methyl-5-hexene. Copolymers of MCHEMA and styrene were prepared in 1,4-dioxane solution at 60 °C using 2,2,-azobisisobutyronitrile as the initiator. They were characterized by IR, 1H NMR, and 13C NMR spectra. Their compositions were determined by the 1H NMR technique. The monomer reactivity ratios were determined by the Fineman,Ross, Kelen, Tüdös, and Yezrielev,Brokhina,Roskin method. Thermogravimetric analysis of the copolymers was carried out under a nitrogen atmosphere. The glass-transition temperature of the copolymers as determined by differential scanning calorimetry agreed with the Flory,Fox relationship. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1756,1763, 2002 [source] Synthesis and Characterization of Poly(N -vinylimidazole- co -acrylonitrile) and Determination of Monomer Reactivity RatiosMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2004Nursel Pekel Abstract Summary: Radical-initiated solution copolymerization of N -vinylimidazole (VIM) and acrylonitrile (AN) was carried out with 2,2, -azobisisobutyronitrile (AIBN) as an initiator in benzene at 70,°C in nitrogen atmosphere. The structure and composition of synthesized copolymers for a wide range of monomer feeds were determined by FTIR, 1H and 13C NMR spectroscopy with the aid of recorded analytical absorption bands for VIM (667 cm,1, CN of imidazole ring) and AN (2,242 cm,1, CN group), as well as by using the areas of proton and carbon atom signals from corresponding functional groups of monomer units. Monomer reactivity ratios for VIM (M1)-AN (M2) pair were determined by nonlinear regression (NLR), Kelen,Tüdös (KT) and Fineman,Ross (FR) methods. They were found to be r1,=,0.24 and r2,=,0.15 for the NLR method, r1,=,0.22 and r2,=,0.094 for the KT method, and r1,=,0.24 and r2,=,0.12 for the FR method, respectively. The relatively high activity observed of VIM growing macroradical and the results of FTIR and 1H NMR structural analysis of copolymers suggest the formation of complexed linkages between monomers and growing radicals in chain propagation reactions. Similar complexation between monomer,comonomer units in the structure of formed macromolecules showed an increase in isotactic triad fractions in the copolymer. Complex formation between the imidazole ring and nitrile group in both the monomer mixture and chain growing reactions. [source] Emulsion copolymerization of styrene and sodium styrene sulfonate: kinetics, monomer reactivity ratios and copolymer propertiesPOLYMER INTERNATIONAL, Issue 1 2009Dhamodaran Arunbabu Abstract BACKGROUND: The synthesis of poly[styrene- co -(sodium styrene sulfonate)], poly(S- co -NaSS), with a high loading of sulfonate groups is of current interest owing to its potential use in numerous areas. A series of these copolymers with various sulfonate loads were synthesized using the emulsion polymerization technique with a study of the copolymerization kinetics, monomer reactivity ratio and copolymer properties. RESULTS: The copolymerization kinetics are significantly enhanced with an increase of NaSS feed in the polymerization. Monomer reactivity ratios were determined from NMR data by employing the Fineman,Ross and Kelen,Tüdös methods. Styrene (r1) and NaSS (r2) reactivity ratios are 0.5 and 10, respectively. The colloidal particle size of the copolymers depends upon the NaSS composition. The thermal stability of the copolymers is greatly enhanced with higher NaSS content in the copolymer backbone. Higher glass transition temperatures are observed for the copolymers with higher NaSS content. CONCLUSION: The reactivity ratio values suggest that styrene prefers to form copolymers whereas NaSS produces homopolymers. It is also found that styrene copolymerization with NaSS is only twice as fast as homopolymerization. In contrast, NaSS homopolymerization is ten times faster than NaSS copolymerization with styrene. The NaSS content in the copolymer backbone affects the thermal stability and the glass transition of the copolymers. Copyright © 2008 Society of Chemical Industry [source] Effect of polymerization method on structure and properties of cationic polyacrylamideJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Yinghua Shen Abstract Acrylamide and 2-(methacryloyloxy)ethyltrimethylammonium chloride (AM/MADQUAT) copolymers were synthesized by solution and inverse microemulsion polymerization using (NH4)2S2O8/NaHSO3 as redox initiator at the same feed mole ratio, and their microstructure, such as sequence distribution and composition distribution, was calculated from monomer reactivity ratios of different polymerization methods. The results show that charge distribution is more uniform for copolymer prepared in inverse microemulsion than that in solution, and copolymer composition distribution is close to unity, and maintains approximately at the feed ratio. Furthermore, the influence of the two structures of cationic polyacrylamides on kaolinite floc size and effective floc density, reduction of Zeta potential and floc compressive yield stress had been investigated at pH 7. The results show that the kaolinite floc size and effective floc density are strongly dependent upon copolymer microstructure, with greater floc size and lower effective floc density being observed for copolymer prepared in inverse microemulsion than for that in solution. Copolymer microstructure has a marked effect on the Zeta potential, whose reduction in the magnitude was much greater in the presence of copolymer prepared in inverse microemulsion than that in solution. Greater compressive yield stress was achieved for the strong flocs produced by copolymer prepared in inverse microemulsion than for the weak flocs produced by that in solution. The difference in flocs compressive yield stress may be attributed to flocs structure. Therefore, in this article, a correlation between the cationic polyacrylamide structure and flocculation property for kaolinite suspension was established. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Kinetics and monomer reactivity ratios of N -vinylpyrrolidone and ,-terpineolJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Sarika Yadav Abstract The radical copolymerization of ,-terpineol with N -vinylpyrrolidone (N -VP) in dioxane at (80 ± 0.1)°C for 1 h in the presence of benzoylperoxide follows ideal kinetic and results in the formation of random copolymer as evidenced from the value of reactivity ratios as r1 (N -VP) = 0.23 and r2 (,-terpineol) = 0.025, which have been calculated by the Kelen-Tüdos method. The overall activation energy is computed to be 28 kJ/mol. The FTIR spectrum of the copolymer shows the presence of bands at 3507 cm,1 due to alcoholic group and 1717 cm,1 due to > CO group. The Alfrey-Price parameters for ,-terpineol has been calculated as 0.024 and ,2.66. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 476,481, 2007 [source] Preparation of amphiphilic statistical copolymers of 2-hydroxyethyl methacrylate with 2-diethylaminoethyl methacrylate, precursors of water-soluble copolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2002Gerardo Martinez Abstract Statistical copolymers of 2-hydroxyethyl methacrylate (HEMA) and 2-diethylaminoethyl methacrylate (DEA) were synthesized at 50 °C by free-radical copolymerization in bulk and in a 3 mol L,1N,N,-dimethylformamide solution with 2,2,-azobisisobutyronitrile as an initiator. The solvent effect on the apparent monomer reactivity ratios was attributed to the different aggregation states of HEMA monomer in the different solvents. The copolymers obtained were water-insoluble at a neutral pH but soluble in an acidic medium when the molar fraction of the DEA content was higher than 0.5. The quaternization of DEA residues increased the hydrophilic character of the copolymers, and they became water-soluble at a neutral pH when the HEMA content was lower than 0.25. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2427,2434, 2002 [source] Copolymerization of (2-phenyl-1,3-dioxolane-4-yl)methyl methacrylate with alkyl methacrylates: Reactivity ratios and copolymer characterizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2002Mehmet Co Abstract The radical copolymerizations of (2-phenyl-1,3-dioxolane-4-yl-)methyl methacrylate (PDMMA) with methyl methacrylate (MMA), ethyl methacrylate (EMA), and butyl methacrylate (BMA) were studied in dioxane at 60 °C with benzoyl peroxide as an initiator. The glass-transition temperatures of poly(PDMMA- co -MMA), poly(PDMMA- co -EMA), and poly(PDMMA- co -BMA) varied from 130 to 138 °C, from 100 to 134 °C, and from 63 to 122 °C, respectively, depending on the copolymer composition. Along with some physicochemical properties and thermal stability investigations of the copolymers, the monomer reactivity ratios were also determined with the conventional Finemann,Ross and Kelen,Tüdös linearization methods. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1184,1191, 2002 [source] New Poly(sodium carboxylate)s Based on Saccharides, 1.MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 18 2002Characterization of Ionic Allyl Glycoside Polymers, Synthesis Abstract New poly(sodium carboxylate)s, containing monosaccharide side groups with ether linkages to the main chain, are presented as substitutes for water-soluble homo- and copolymers of acrylic acid. Neutral and ionic allyl glycoside monomers, namely allyl- , - D -galactopyranoside and allyl- , - D -glucofuranosidurono-6,3-lactone, were synthesized by Fischer glycosidation. These monomers were copolymerized with maleic anhydride and itaconic acid in aqueous and nonaqueous solution. The corresponding copolymers with different structures, degrees of functionalization, and charge densities were characterized by 13C NMR spectroscopy, molecular-weight measurements, and intrinsic viscosity [,] determination. From these, the monomer reactivity ratios and Mark,Houwink relations were established (see Figure). Copolymerization curves of maleic acid copolymers 6 and 10. M1: mole fraction of allyl monomer 2, and 5, in the feed; m1: mole fraction of allyl monomer in the copolymer. The dashed line shows the course of an ideal alternating copolymerization (excepted: M1,=,0 mol-%, M1,=,100 mol-%). [source] Emulsion copolymerization of styrene and sodium styrene sulfonate: kinetics, monomer reactivity ratios and copolymer propertiesPOLYMER INTERNATIONAL, Issue 1 2009Dhamodaran Arunbabu Abstract BACKGROUND: The synthesis of poly[styrene- co -(sodium styrene sulfonate)], poly(S- co -NaSS), with a high loading of sulfonate groups is of current interest owing to its potential use in numerous areas. A series of these copolymers with various sulfonate loads were synthesized using the emulsion polymerization technique with a study of the copolymerization kinetics, monomer reactivity ratio and copolymer properties. RESULTS: The copolymerization kinetics are significantly enhanced with an increase of NaSS feed in the polymerization. Monomer reactivity ratios were determined from NMR data by employing the Fineman,Ross and Kelen,Tüdös methods. Styrene (r1) and NaSS (r2) reactivity ratios are 0.5 and 10, respectively. The colloidal particle size of the copolymers depends upon the NaSS composition. The thermal stability of the copolymers is greatly enhanced with higher NaSS content in the copolymer backbone. Higher glass transition temperatures are observed for the copolymers with higher NaSS content. CONCLUSION: The reactivity ratio values suggest that styrene prefers to form copolymers whereas NaSS produces homopolymers. It is also found that styrene copolymerization with NaSS is only twice as fast as homopolymerization. In contrast, NaSS homopolymerization is ten times faster than NaSS copolymerization with styrene. The NaSS content in the copolymer backbone affects the thermal stability and the glass transition of the copolymers. Copyright © 2008 Society of Chemical Industry [source] Synthesis and monomer reactivity ratios of ethyl ,-acetoxyacrylate and acrylic acid copolymersPOLYMER INTERNATIONAL, Issue 11 2005Cédric Loubat Abstract The synthesis of ethyl ,-acetoxyacrylate (EAA) and the study of its radical polymerization is described. We report the monomer reactivity ratios for copolymers of EAA and acrylic acid (AA) using three different methods: the Jaacks, the Macret and the Fineman,Ross methods. Copolymers were obtained by free radical polymerization initiated by 2,2,-azobisisobutyronitrile in acetonitrile solutions and were analyzed by NMR and HPLC. The HPLC analysis was used to determine the molar fractions of EAA and AA in the copolymers. The reactivity ratios were estimated to be close to 1 for each monomer. Thus, copolymers of poly(acrylic acid) bearing some biodegradable units of EAA in the chain were subsequently prepared. The study of the hydrolysis of these units shows that only basic conditions were efficient to lead to hydrolyzed monomer units. Copyright © 2005 Society of Chemical Industry [source] A kinetic study of the copolymerization of substituted anilines by 1H NMR,POLYMER INTERNATIONAL, Issue 10 2002Ida Mav Abstract We investigated the kinetics of oxidative chemical copolymerization of 2-methoxyaniline (OMA) with the following acidic substituted anilines (ANIAs): 2-aminobenzoic acid, 3-aminobenzoic acid, 2-aminobenzenesulfonic acid and 3-aminobenzenesulfonic acid by monitoring monomer depletion using 1H NMR spectroscopy. In order to characterize kinetically these new copolymerization systems, a semi-empirical kinetic model for copolymerization systems with a large difference in monomer reactivities was used, whereas the monomer reactivity ratios were determined by employing the Kelen,Tüdõs (KT) method. Owing to the much higher reactivity of OMA compared to that of ANIA monomers, the conversion of OMA starts before that of ANIA and both the initiation and propagation rates are higher than those for ANIAs. The ANIA end-conversion is much smaller (from 21 to 31%) than that of OMA (from 75% to 90%). © 2002 Society of Chemical Industry [source] | ||||||||||